Electric resolver for vectorial summation and resolution



2 Sheets-Sheet l OLVER FOR VECTORIAL .aezb Y I June 1, 1954 E. GRANAT ELECTRIC RES SUMMATION AND RESOLUTION Filed Nov. 26, 1949 FIG. I

June 1,1954

1 EJGRANAT' 2,679,976 ELECTRIC RESOLVER FOR VECTORIAL SUMMATIONJ XND RESOLUTION Filed Nov; 26, 19.49 2 Sheets-Sheet 2 Patented June 1, 1954 UNITED STATE TENT OFFICE ELECTRIC RESOLVER FOR VECTORIAL SUMMATION AND RESOLUTION Claims priority, application France December 6, 1948 4 Claims. 1

This invention relates to electrical resolvers.

In prior patents I have described machines allowing to effect calculations of difierent sorts by means of purely electrical devices which, according to the kind of calculations to be made, utilize either linear or sinusoidal potentiometers and various compensation devices enabling the various elements of the resolver to be arranged in series without provoking any reaction of one of these elements on those preceding it.

The present invention is concerned with elements of similar electrical resolvers which however do not carry out simple operations such as additions, subtractions, multiplications and divisions, but obtain by electrical means the geometric sum of several values and in particular the determination of any triangle and generally the resolution of a vector into its components in different directions and the determination of a vector from two components in any directions.

In the drawings afiixed to this specification and forming part thereof various embodiments of my invention are illustrated diagrammatically by way of example.

In the drawings,

Figs. 1, 2, 2a and 2b are diagrams illustrating different problems to be solved with the aid of devices according to this invention.

Fig. 3 illustrates a calculating device operated with direct current, with the aid of which the vector AC in Fig. 2 can be calculated, if the length of the vectors AB and BC and the angle enclosed by them are known.

This device allows of solving any triangle, of which two sides and the angle opposed to one of them are known, as illustrated in the diagram of Fig. 2a, or one side and the two adjacent angles are known, according to the diagram of Fig. 2b.

Fig. 4 is a purely schematic showing of the way in which a field of predetermined magnitude can be created in a resolver according to this invention by a transmitting machine, while Figs. 5 and 6 are diagrams showing by way of example a magnetic and an electronic relay adapted for use in the device here in View.

These electromagnetic devices comprise two identical transmitting machines and a resolver. They have become known mainly by studies I published and are described in detail in the specification of my Patent No. 1,567,941, dated December 29, 1925, for A Complete Electric Distant Control Apparatus. In the present invention they are combined in a novel manner for the obtainment of certain predetermined results.

The device of Fig. 3 comprises two identical machines 33 and 36 which are fed respectively with the voltages U1 and U2, being direct current motors in which the motor field winding 35 and the armature 36 are fed in parallel. llhey have mounted above the commutator 3? a system 49 of movable brushes arranged at angles of 120 relative to each other and are connected to a receiver machine d2 by means of contact rings. This latter machine d2 resembles a dynamo with two distributed field windings 4t and M and an armature carried along at constant speed by a motor 9! and provided with a commutator 86 on which slide two pairs 45 and it of brushes (each pair being insulated electrically from the other) which are mounted on a support #9 constituted by two arms extending at right angles to one another.

The brushes it of the transmitters are connected to three homologous points spaced 120", of the inductors 43 and. 54. The brushes it are connected to the, entrance terminals of a mag-- netic, or preferably an electronic, relay ll which controls the stopping and the running in one or the other direction of a motor 8 which carries along one of the movable members of the apparatus according to the problem to be solved (resolving of the triangles, Figs. 2, 2a or 2b).

The device il serving for starting the motor in one or the other sense has been designated by the general term of relay. Obviously this device, which is not in itself part of the invention here described and claimed, may, according to the circumstances of each individual case, be of any electromagnetic or electronic type. In the case here in View the use of an electronic relay acting as amplifier offers an important advantage.

In order to assure the greatest precision, it is necessary to be able to ascertain the extremely feeble voltage which would correspond to a very minute displacement and to utilize this voltage for the control of the motor.

An electronic amplifying relay fulfills these conditions by permitting to obtain by a very low voltage to be applied on the entering side (first grid circuit), a voltage at the outgoing side (last plate circuit) suiiicing for actuating, directly or indirectly, the commutator controlling the starting, in one or the other sense, of the motor M.

In Fig. 4 that part of the resolver 52 which represents one of the coils, for instance i l, 15 illustrated under the form of an inductor 826 With 6 pole pieces arranged pairwise in diametrical opposition and displaced from each other 3 so that the windings l2l-i2l, l22-l22 and 123-423 which embrace the pole pieces, are fed with 3-phase current, whereby a rotating magnetic field is created at Hi).

It should be understood that instead of the simple device shown in the drawing, any other system of windings might be used which when fed with B-phase current, would produce a rotating field.

The transmitting machine (iii is represented in this sketch only by its commutator 3'! on which can turn the 3 brushes 40.

As is well known, in a transmitting machine such as here shown (33 and 36) fed with con tinuous current, the segments of the commutator 3'1 possess at any time potentials depending on the position the segment occupies in space at that moment and these different potentials are distributed on the commutator 3'! in accordance with a mainly sinusoidal law.

Therefore if on this commutator were mounted two brushes in diametrical opposition and were made to turn on the commutator, there would be obtained on these brushes an alternating current the intensity of which would depend on the feed voltage U2 of the machine while its frequency would depend on the speed of revolution of the brushes.

It is easy to see that if the pair of brushes were replaced by 3 brushes 4G displaced 120 relative to each other, one might collect on them a 3-phase current, the intensity of which would depend on the feed voltage U2 of the machine, while its frequency would depend on the speed of revolution of the brushes at on the commutator.

If one now connected these 3 brushes ie with the 3 windings, as is shown in Fig. 4, one generates in this resolver a rotating field, the constant intensity of which depends on the feed voltage U2 of the transmitting machine and which will turn in synchronism with the 3 brushes 40. Such a transmitting machine is described more in detail in my patent mentioned hereinabove.

In the case of the present invention, the 3 brushes '40 do not revolve on the commutator but remain fixed in the position at which they have been set. Under these conditions the field produced in the resolver is not a rotating field any more. It will retain a fixed direction which depends on the relative adjustment of the brushes G and its well determined intensity will depend on the feed voltage U2. In this manner the transmitting machines 36 will create the flux (p2, while the machine 33 which feeds the winding 33, will create in the same manner the flux c1.

Since the magnitude of the flux (p2 (or field intensity) depends solely on the feed voltage U2 of the transmitting machine, while its orientation depends solely on the position of the brushes as, it is clear that if, while leaving the brushes in their position, the voltage U2 is varied in some way, the field will retain the same direction, but its intensity will vary when the transmitting machine is fed a variable voltage U2, one obtains in the resolver a variable flux (#2 of predetermined direction. The flux resulting from the two variable fluxes 1 and (p2 will thus be of variable magnitude and fixed as to its direction.

The armature currents can easily be tapped off the armatures 45 and 4% (Fig. 3) by means of brushes gliding on the rings.

As regards the nature of the relay fi'i, which does not form as such a part of this invention,

two examples are shown in Figs. 5 and 6 for an electromagnetic relay and an electronic relay, respectively. The relays must be reversing, which means that they must change the direction of the current feeding the motor 33. lhis motor which does not present any special aspect, might obviously be represented by a mere rcctangle.

The electromagnetic relay shown in Fig. 5 would be of the polarized type, for which 1 1y different forms are known, i. e. of a type in i the armature occupies different positions accon. ing tn the direction of the current feeding the relay.

In Fig. 5 this relay is represented by a winding Hill connected to the brushes at the end of the arm 46 and by two armatures H32 and which may take up three positions:

1. When the relay is not excited, a position of rest, in which these armatures do not make any contact;

2. When the relay is excited, 2 working positions, at which these armatures are connects to the upper and lower contacts according to the direction of the current passing through the winding illi. This figure shows clearly that the current from the battery 1% which feeds the motor t3, passes through this motor in one or the other direction according to whether the armatures Hi2 and H13 are in touch with the upper or lower contacts.

Fig. 6 shows, also in a purely diagrammatimanner, an electronic reversing relay which iconstituted by two triodes Hi5 and Hit, the gri circuits of which are connected to the brushe 49, however in opposite sense, which means thaevery brush is connected to the grid of one tried and the cathode of the other triode. If th grids are biased, for instance by the elements iii! and do not allow the passage of the electronic current unless the potential of the brush 49 connected to this grid is positive with respect to the potential of the other brush, the electronic current will always pass only through a single one of the triodes at a time and it will not pass through any triode when the brushes have the same potential. If the plate circuits of the triodes are connected, however in opposite direction to the motor, as represented in the figure, it is clear that according to whether it will be one or the other brush 4%! which has the highest potential, it will also be one or the other of the triodes Hi5 and [66, through which an electronic current will pass and that consequently the current passing through the motor will be directed in one or the other sense.

Apart from the general advantages, set out above, offered by the use of an electronic amplifier relay, it also offers another important a-:1-- vantage in the case of the device shown in Fi 3 which comprises a revolving armature. Such a relay merely requires a voltage to be applied to its entrance side (first grid circuit), while the intensity of the grid current may be considered as altogether negligible. Under these conditions the armature of the resolver does not produce any discharge of current in the outer circuit.

In consequence thereof the machine will not produce any phenomenon of armature reaction which might displace the direction of the 1 sulting flux and, owing to the position, corr spending to zero voltage.

When the transmitting machines are supplied with direct current voltages U1 and U2, each of them obviously produces in one of the field magnets of the resolver a flux 1 or 2, the value of which depends from the values of U1 and U2 and from the direction for which the brushes 4!) are adjusted on the collectors of their respective ma chines. These two fluxes result in a flux 3 which is obtained according to the rule of a parallelogram, as indicated on the drawing.

In order to resolve a triangle of which two sides and the angle between them (ABBC and {3 in Fig. 2) are known, one connects the motor 48 mechanically with the rotary support 49. If one then gives to the voltages U1 and U2 values proportional to the sides AB and BC of the triangle in Fig. 2, while so adjusting the brushes 46 that the fluxes 1 and (p2 enclose between them an angle of 180,8, it can be seen that the triangles having as their sides (#1 and 2 and 3 are equal to the triangle ABC of Fig. 2.

If then the system of brushes 45, it occupies the position shown in the drawing, 1. e. if the line of the brushes 4% coincides with the direction of the resulting flux ea, it will be seen that the voltage U3 between these two brushes is proportional to 3 and therefore is to be found on the third side AC of the triangle ABC, whose angles 'y and 6 are indicated by the adjustment of the brushes ill of the transmitting machines.

On the other hand the two brushes carry the same voltage which has for its consequence that the relay 4? is not excited and therefore the motor 48 remains at rest.

If however the brushes 45, 56 were not in the position shown on the drawing, then the brushes would carry different voltages and the relay 4? would move into one of its operative positions, the motor 48 would start and would carry along the support #9, until the brushes d5, 56 occu pied the position shown in the drawing at which the motor d8 would come to a standstill. The value of the voltage U3 and the adjustment of the brushes would then indicate the elements sought for, viz. AC, 7 and 6 of the triangle ABC.

The same device allows to resolve the triangles of Figs. 2a and 2b by mechanically coupling the motor 48 with one of the brush systems in the first case and with a potentiometer 92 which regulates U2 in the second case.

In order to resolve the triangle 2a, in which one knows two sides and the angle opposite one of them, one regulates the voltages U1 and U2 in such manner that they become proportional to the two known sides AB and BC of the triangle, one fixes the support 59 in position and so adjusts the position of the brush system 553 of the transmitting machine that the flux 2 which is produced, encloses with the line of brushes the given angle 7. In that case the motor 48, acting on the brush system of the transmitting machine 33, shifts them. into the position in which the brushes 55 carry equal voltages. As in the case above discussed, the final angle at which these brushes are positioned, and the value of the voltage Us at the brushes #5 indicate the elements of the triangle ABC looked for.

In order to resolve the triangle 2?), of which one side AB and the adjacent angles ,8 and 5 are known, one couples mechanically the motor 8 with a rheostat 92 which enables the voltage U2 to be adjusted. After having fixed in. place the support 49, one so adjusts the system of brushes it of the transmitting machines that the fluxes 1 and 2 enclose with the line of brushes it the angles [3 and 8 whereupon, while leaving U1 in fixed position, one allows the motor 43 to adjust U2 by acting on the rheostat 92.

When the motor stops running, it is because the brushes 46 carry the same voltage and, based on the same reasoning as before, the values of U2 and U3 are in the same relation with the sides AC and BC as the voltage U1 with the known side AB.

It should be noted that since the armature is rotated by the motor 9! at a constant number of revolutions (which might be determined), the device acts like an amplifier.

The voltages U1 and U2 give rise to excitation current of little intensity, Whereas the resulting voltage Us is formed by the armature of the machine which is capable of generating a considerable current depending on the dimensions and number of revolutions of the armature, the power derived from the working circuit being provided by the driving motor and not by the calculation circuit which provides the voltages U1 and U2.

Apart from this, it has been assumed in the foregoing description that the driving motor 9i would run at constant speed, but it is possible to adjust or vary the speed as desired by any conventional means such as a resistor iii con nected to the motor 9i. In that case the voltage U3 is proportional to both the flux 53 and the speed of the driving motor, i. e. to their product, so that by choosing for this speed a value proportional to a predetermined coefficient, the voltage Us would be multiplied by this coefficient. The machine could thus be used for obtaining in one operation the geometric sum of two vectors and the multiplication of the result by a predetermined figure.

The foregoing description concerns a certain number of devices of the electromagnetic type which allow of determining the algebraic sum of vectors as well as their resolution according to given directions. The embodiments of this invention disclosed in the specincation and in the drawing are merely meant to be examples without in anyway limiting the scope of the claims which I intend to cover all variations included by their wording.

I claim:

1. An electrical resolver for the solution of triangles, the geometrical addition of vectors, and the resolution of a vector into components thereof, comprising two polyphase stator windings, a rotor winding, a commutator connected to said rotor winding, two polyphase generators exciting, respectively, said stator windings with polyphase voltages producing fluxes in said stator windings, respectively, at predetermined angles, means including an auxiliary motor connected to said commutator for rotating said rotor Winding at a constant speed, a first pair of diametrically opposite brushes arranged in contact with said commutator, a second pair of brushes arranged in contact with said commutator apart from said first pair of brushes, a relay connected to said first pair of brushes, voltage taps connected to said second pair of brushes, and electromagnetic means fed by said rela and connected to move said first and second pairs of brushes so as to reduce to zero the potential difference across said first pair of brushes.

2. An electrical resolver for the solution of triangles, the geometrical addition of vectors, and the resolution of a vector into components thereof, comprising two polyphase stator windings, a 1'0- tor winding, a commutator connected to said rotor winding, two polyphase generators exciting, respectively, said stator windings with polyphase voltages producing fluxes in said stator windings, respectively, at predetermined angles proportional to two sides of the triangle, respectively, means including an auxiliary motor con nected to said commutator for rotating said rotorwinding at a constant speed, a first pair of diametrically opposite brushes arranged in contact with said commutator, a second pair of brushes arranged in contact with said commutator 90 apart from said first pair of brushes, a relay connected to said first pair of brushes, voltage taps connected to said second pair of brushes, means for connecting said voltage taps to a voltage proportional to the third side of the triangle, and electromagnetic means fed by said relay and connected to move said first and second pairs of brushes so as to reduce to zero the potential difference across said first pair of brushes.

3. An electrical resolver for the solution of triangles, the geometrical addition of vectors, and the resolution of a vector into components there- 01", comprising two polyphase stator windings, a rotor winding, a commutator connected to said rotor winding, two polyphase generators exciting, respectively, said stator windings with polyphase voltages producing fluxes in said stator windings, respectively, at predetermined angles proportional to two sides of the triangle, respectively, means including an auxiliary motor connected to said commutator for rotating said rotor winding at a constant speed, a first pair of diametrically opposite brushes arranged in contact with said commutator, a second pair of brushes arranged in contact with said commutator 90 apart from said first pair of brushes, a relay connected to said first pair of brushes, voltage taps connected to said second pair of brushes, means for connecting said voltage taps to a voltage proportional to the third side of the triangle, and electroinagnetic means fed by said relay and connected to move said first and second pairs of brushes so as to reduce to zero the potential difference across said first pair of brushes, said rotor winding acting as an amplifier having the output power thereof supplied by said auxiliary motor.

4. An electrical resolver for the solution of triangles, the geometrical addition of vectors, and the resolution of a vector into components thereof, comprising two polyphase stator windin s, a rotor winding, a commutator connected to said rotor winding, two polyphase generators exciting, respectively, said stator windings with polyphase voltages producing fluxes in said stator windings, respectively, at predetermined angles, means including an auxiliary motor connected to said commutator for rotating said rotor wind ing at a constant speed, means for adjusting the speed of said auxiliary motor, a first pair of diametrically opposite brushes arranged in contact with said commutator, a second pair of brushes arranged in contact with said commutator 90 apart from said first pair of brushes, a relay connected to said first pair of brushes, voltage taps connected to said second pair of brushes, and electromagnetic means fed by said relay and connected to move said first and second pairs of brushes so as to reduce to zero the potential difference across said first pair of brushes.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,030,762 Pestarini Feb. 11, 1936 2,404,387 Lovell July 23, 1946 2,407,325 Parkinson Sept. 10, 1946 2,465,624 Agins Mar. 29, 1949 2,471,315 Dehmel May 24, 1949 2,519,180 Ergen Aug. 15, 1950 2,532,158 Ewing Nov. 23, 1950 FOREIGN PATENTS Number Country Date 164,765 Great Britain June 23, 1921 

